Finding Chart returns a JPEG image centered on (ra,dec), of size (height x width)
where the image is scaled to an arbitrary scale (scale). Various drawing options can be specified (opt).

Navigate lets you interactively navigate the sky, by clicking and zooming.

Image List is a cutout service that
generates small JPEG images for up to 1000 user-provided positions on the sky.

Quick Look lets you view basic data for an object, such as its position, magnitude, and redshift

Explore
lets you interactively explore
the various properties of individual objects.

Search allows you to
search the database for sky positions, objects with a
certain brightness, and and various other criteria.
You can even enter free-format SQL queries, or use a simple form to search the database.

Object Crossid allows you to upload
search the database for sky positions, objects with a
a list of object positions, and returns the SDSS objects
which are within a certain radius of those positions.
A few simple upload formats are supported.